反应详情

Under anhydrous conditions at 0° C. a solution of 8-oxo-2,2,5,7-tetramethyl-7-(hydroxymethyl)-3-oxa-1-azabicyclo[4.2.0]octane (60 mg) in 0.6 ml ether is treated with powdered potassium hydroxide (19 mg). After a period of 15 minutes, o-nitrobenzyl chloroformate (65 mg) is added to the reaction mixture. Stirring is continued at 25° C. for an additional 15 hours. The mixture is partitioned between 1 M pH 7 phosphate buffer and more ether. The ether phase is washed with water and brine, dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives a colorless oil. Purification by preparation thick-layer chromatography on silica gel developing with 1:9 ethylacetate/benzene gives 8-oxo-2,2,5,7-tetramethyl-7-(o-nitrobenzylcarbonyldioxymethyl)-3-oxa-1-azabicyclo-[4.2.0]octane as a mixture of diastereomers.

1. waitis continued at 25° C. for an additional 15 hours
2. customThe mixture is partitioned between 1 M pH 7 phosphate buffer and more ether
3. washThe ether phase is washed with water and brine
4. dry with materialdried over magnesium sulfate
5. filtrationfiltered
6. customEvaporation of the filtrate under reduced pressure
7. customgives a colorless oil
8. customPurification
9. customby preparation thick-layer chromatography on silica gel developing with 1:9 ethylacetate/benzene